The present disclosure relates to deep trench isolation techniques, such as used in photovoltaic devices.
Photovoltaic devices are used in a wide variety of electronics applications ranging from image sensors, to optical detectors, to telecommunications, etc. Many photovoltaic devices utilize an array of pixels, which include photodiodes that convert an image into digital data. A photodiode consists of a p-n junction arranged between an anode and a cathode. When incident radiation from an image is absorbed near a depletion region of the p-n junction, an electron-hole pair is created. The electron is drawn to cathode and the hole is drawn to the anode to produce a photocurrent.
Some photodiodes are formed directly on a semiconductor substrate alongside an integrated circuit during a semiconductor manufacturing process. These photodiodes provide an advantage of lower power consumption, smaller size, faster data processing, and lower manufacturing cost than photodiodes formed external to the semiconductor substrate. The properties of a photodiode formed on a semiconductor substrate are determined from the bandgap of the semiconductor substrate, because the bandgap determines what wavelengths of incident light will excite electron-hole pairs to produce the photocurrent.